Portfolio Rebalancing Calculator (Pro) United States

What the calculator produces

Sum stocks, bonds and cash, add any new contribution, and you have the portfolio total. Apply each target percentage to that total to get the value each asset class should hold. Subtract what you hold from what you should hold, and the difference is the trade.

• Target value = total portfolio value × target percentage
• Trade = target value − current value

Positive is a buy, negative is a sell. With no new contribution the buys and sells offset exactly and the portfolio value is unchanged; with one, the total rises by the amount added and the trades absorb it.

This is a Pro tool, and the trade schedule is calculated on our server.

Why allocations drift

Different assets grow at different rates, so the mix you set is not the mix you have a year later. A strong equity market lifts stocks as a share of the total without you buying a single additional share.

Drift changes your risk. A 70/20/10 split of stocks, bonds and cash carries a specific level of expected volatility. When drift takes stocks to 80 per cent, the portfolio is more aggressive than your plan and will behave that way in the next drawdown. Rebalancing makes you trim what has run up and add to what has lagged, which is the opposite of what instinct suggests.

A worked example without new money

You hold $60,000 in stocks, $30,000 in bonds and $10,000 in cash, for a $100,000 total. Your targets are 70 per cent stocks, 20 per cent bonds and 10 per cent cash.

Applying the targets gives $70,000, $20,000 and $10,000:

• Stocks: target $70,000 against $60,000 held, so buy $10,000
• Bonds: target $20,000 against $30,000 held, so sell $10,000
• Cash: target $10,000 against $10,000 held, no trade

The total stays at $100,000 and only the composition changes.

The same example with a contribution

Now add $20,000 of new money. The total becomes $120,000, so the stock target rises to $84,000, the bond target to $24,000 and the cash target to $12,000. Against holdings of $60,000, $30,000 and $10,000, the trades become a $24,000 stock purchase, a $6,000 bond sale and a $2,000 cash addition.

Without the contribution you sold $10,000 of bonds. With it, the new money funds most of the correction and the sale shrinks to $6,000. A large enough contribution removes the sale altogether, and a correction made by buying creates no taxable gain.

How the account type changes the tax

The arithmetic is the same in every account. The tax bill is not.

In a 401(k), a traditional IRA or a Roth IRA, trading is not a taxable event. You can sell an appreciated position and buy something else with no immediate consequence. Retirement accounts are the natural place for trades you would otherwise avoid, and many investors hold their bond allocation inside a tax-deferred account for that reason: rebalancing trades cost nothing in tax there, and the bond interest is sheltered too.

In a taxable brokerage account, selling realizes a gain, and the rate depends first on the holding period. A position held more than a year gets long-term treatment, taxed at zero, 15 or 20 per cent, with the zero band running up to $49,450 of taxable income for a single filer and $98,900 for a married couple filing jointly, and the 20 per cent rate starting above $545,500 and $613,700. A position held a year or less is a short-term gain taxed at your ordinary income rate, which for most people costs noticeably more. If a winner is close to the one-year mark, waiting before you trim it usually pays.

The 3.8 per cent net investment income tax also applies once modified adjusted gross income passes $200,000 for a single filer or $250,000 filing jointly, so a large rebalance in a high-income year can be taxed above the headline capital gains rate.

Harvesting losses at the same time

You are already reviewing every position during a rebalance, so it is a good moment to look for losses. Realized losses offset realized gains dollar for dollar, and if losses exceed gains you can deduct up to $3,000 against ordinary income in the year, with the rest carried forward indefinitely.

The constraint is the wash sale rule. If you buy substantially identical stock or securities within 30 days before or 30 days after the sale, the loss is disallowed and added to the basis of the replacement holding instead. That is a 61-day window around the sale, not just the 30 days after it, and it applies across your accounts. The usual workaround is to buy a similar but not substantially identical fund, which keeps you invested in the asset class and preserves the loss.

Setting a rebalancing trigger

A calendar rule reviews the portfolio on a fixed date each year. A threshold rule acts only when an asset class has drifted more than a set number of percentage points from target, so it trades less often in quiet markets and more often in volatile ones. Either works if you stick to it. Rebalancing because of how the market feels brings back the guesswork the rule is meant to remove.

Before you place the trades

Check whether each trade is large enough to be worth doing, whether a contribution can fund it instead of a sale, whether any position is close to moving from short-term to long-term treatment, and whether the gain would land in a year you would rather not add income to.

For decisions with tax or suitability implications, confirm the position with a licensed financial advisor who can consider your full circumstances.

This is general information only and not financial advice.

About This Portfolio Rebalancing Calculator

Use this portfolio rebalancing calculator to get an instant estimate based on the figures you enter. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.